


Man or Monster

by MetaAllu



Category: Voltron: Legendary Defender
Genre: Alien Keith (Voltron), Feral Behavior, Hand Jobs, M/M, Mildly Dubious Consent, Monsterization, Nonconsensual Body Modification, by biology but still, half feral keith, initially one-sided sheith, mild body horror, this is all far too much plot im a smut writer please enjoy the results of my suffering
Language: English
Status: Completed
Published: 2020-08-08
Updated: 2020-08-08
Packaged: 2021-03-06 02:00:10
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,488
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25775509
Author URL: https://archiveofourown.org/users/MetaAllu/pseuds/MetaAllu
Summary: keith is slowly turning in a large, purple, fluffy, TERRITORIAL galra, and shiro, his best friend (decidedly NOT his mate) is getting the brunt of it.
Relationships: Keith/Shiro (Voltron)
Comments: 4
Kudos: 69





	Man or Monster

Shiro is the first one to notice something is wrong with Keith, and not just because he’s started growling at people. That’s actually not that far out of character. Like, it’s a bit of a leap, sure, but not a huge one by any means.

But, no, Shiro notices because they’re sparring, and beneath Keith’s hairline is a line of purple fur.

He’s got him pinned down, both of Keith’s hands twisted and pinned beneath his back, and he was lowering his head to tell Keith to yield when he spotted some purple, and, worried he’d hit him hard enough to bruise, he’d stopped to inspect, but, no, it was fur.

“Uh.”

“Shiro?”

It’s probably nothing.

Right?

He tries to convince himself of that, but two days later, Keith bites into an apple and immediately yelps, dropping it and clamping a hand over his mouth. It bounces on the canteen table and rolls to a stop after bumping into Shiro’s tray. Embedded in the flesh of the apple are Keith’s canines and one of his premolars.

“Keith?” Shiro is immediately on his feet and around the table. “What happened?”

When Keith tries to speak, blood pours past his lips and they both go still in shock and alarm.

Lunch is over after that. Neither of them have an appetite left, and they hole up in Shiro’s quarters instead, trying to get the bleeding under control. Three more premolars fall out. Both of them attempt pinching themselves in case this is some sort of very fucked up dream.

No such luck.

Shiro finds himself pacing. He doesn’t bother going to ask Allura. Keith would never abide that. He’s sure if Keith could speak past the two cloths they’ve stuffed into his mouth, he’d tell him to sit down.

He turns on his heel again, and Keith is glaring at him. Abruptly, he sits himself down on the bed beside Keith.

“Okay,” he says. “Okay, let’s check again.”

Carefully, he pulls one of the cloths free, ignoring the smell of iron in the air as he delicately pulls Keith’s lip back to get a better look and gasps when he see two small points coming in where Keith’s bottom canine and premolar were.

“Holy shit. You’re growing new teeth.”

Keith pulls out the other cloth, and when he speaks, it’s with a frankly adorable lisp. “Okay, so it’s probably a Galra thing, right? I’ll ask mom or Kolivan.”

“Right. Good plan,” Shiro agrees, feeling calmer now that they have a potential explanation that’s not just ‘holy shit my best friend’s teeth are falling out’.

Keith fetches his data pad and calls up Krolia.

“Hello, starshine,” Krolia greets.

“Hey, mom. Do you have a couple minutes?”

“Well…” There’s the sound of lasers. “Sure. I can spare a few moments for my son.”

“Uh, my teeth fell out?”

Krolia pauses, and then she laughs. “Oh. I didn’t think you’d go through Galra puberty. How interesting.”

“Mom, I don’t think interesting is the word I’d use to describe this,” Keith groans. “Weird stuff keeps happening. I broke my hair brush the other day.”

“Did you? Well, I’ll send over some reading for you when I have a bit more spare time.”

“Thanks, mom.”

“Of course, my sweet plum. Now, I really have to go.”

More laser fire.

“Uh-huh. Bye. Love you.”

“Love you, too. Bye.”

“Well, I don’t know about you,” Shiro says. “But somehow that didn’t make me feel much better.”

Keith groans. “Me neither.”  
But neither of them could have predicted what would happen next.

First of all, Krolia does send information along in the form of a “So Your Teeth Fell Out” pamphlet which outlines the stages of Galra puberty.

The first stage is an increase in certain hormones, which can create irritability. With someone like Keith, it wasn’t very obvious, but it does explain the growling.

The second stage, much more obvious, thus the name of the pamphlet, is the loss of “baby” teeth as fangs grow in. The sharp new teeth replacing Keith’s canines and first set of premolars are, indeed, very sharp.

“You gonna leave them for the tooth fairy?” Shiro teases.

Keith punches his arm.

Those first two stages are easy enough to deal with. The third mentions, in passing, mating instincts and the importance of pack bonds during this stage to keep Galra going through puberty feeling safe and valued.

Shiro shrugs. “Well, you’ve always got me. You know how much you matter to me.”

Keith nods, and they just kind of forget about it for a while.

Nothing even happens for a week, and then one of the bridge crew flirts with Shiro.

He’s cute enough. He’s never really, like, caught Shiro’s eyes, but he knows his name is Curtis and his favourite colour is mauve. He intercepts Shiro on his way to the canteen.

“Good afternoon, captain!” he says, cheerful as usual and Shiro slows his pace so that the other man can keep pace with him more easily.

“Good afternoon,” Shiro replies, polite.

And then suddenly Curtis is flat on his back and Keith is poised above him, shiny new teeth on display in an obvious threat.

Shiro moves without even thinking, pulling him off with an exclamation of “Keith! No!” But when Keith looks at him over his shoulder, his eyes have gone cat-like and gold, mindless and wild.

The aggression melts away into confusion at the look on Shiro’s face.

“No,” Shiro says again, softly and Keith’s defensive stance fades away as Curtis cowers on the ground, mouth open with shock. Shiro can’t risk looking at him, can’t risk looking away. He has no idea what’s happening, but he knows that Keith will need very little provocation to turn his aggression onto him again.

“He’s not a threat. I’m strong. You’re strong. He can’t hurt us,” he tells Keith calmly. Keith blinks up at him a few more times, and then he nuzzles into his neck, sniffing at it hungrily. It’s weird as hell, but again, Shiro doesn’t need to provoke him right now, so he lets it happen, motioning over Keith’s shoulder for Curtis to run away. He obeys immediately.

It takes a few minutes for Keith to calm down enough to form words, and the first thing out of his mouth is “Sorry.”

“Keith, what the hell was that?” Shiro asks, because it’s one thing if it had been Shiro that Keith had just attempted to murder, but it’s another thing when it’s a random member of his crew.

“Nothing!” Keith says. Shiro stares at him because it was most decidedly NOT nothing. “I- I don’t know!”

And that seems to be the end of the conversation, because Keith excuses himself and then brushes past Shiro, bumping into him in his haste to get away. If Shiro didn’t know better, he’d think Keith was embarrassed.

Shiro, foolishly, thinks that that will be the end of it. Only two days later, Keith practically break’s a cadet’s arm when he interrupts their sparring session. He bares his teeth at him, twisting his arm violently behind his back, eyes going golden and dangerous. Shiro, again, has to physically haul him off.

“Keith!” he says, and tries to ignore how hot his face feels, how GOOD it feels to be protected. Everyone always sees Shiro as the protector, never the other way around. But Keith is protecting him. Keith is… is out of control.

It happens twice more in the span of a week.

He doesn’t tell Keith that he’s calling his mom, because the last thing he needs is to embarrass him even more. He looks so humiliated after each instance, and reminding Keith that they’re pack and they’re safe is working less and less.

He feels like his face is on fire as he explains the situation. Krolia is scrutinizing him, a light furrow in her brow as if something is happening which she didn’t expect. That doesn’t feel like a good sign.

“Well, Shiro.” She folds her arms and leans back in her seat. She looks a little like she’s about to threaten his life. He swallows. Hard. “It seems Keith’s Galra side is convinced you’re his mate.”

“What?” Shiro says. He feels a lot like the things on that Youtube account by a Russian man with a hydraulic press. “No. That can’t be right. Keith doesn’t feel that way about me. I would have noticed if my best friend was- if he liked me.”

Krolia raises an eyebrow at him. It reminds him so much of Keith that he starts to blush even harder.

“Thank you for your insight,” he manages to choke out before ending the call and surrendering to the urge to crawl into bed and just be with his thoughts for a while.

Keith thinks Shiro is his mate. That would explain the nuzzling. And the aggression. Does… Keith think other people are trying to steal him? Does Keith even know what he’s doing? More importantly, what does SHIRO do now?

He has to let him down easy. Very, VERY easy. He doesn’t feel that way about him, even if the protectiveness has been nice.

Also, Keith has been extra snuggly on group movie nights, and his warmth has been quite welcome against Shiro’s side. But that’s just because he likes the contact! Nothing else! It has nothing to do with how good he smells or how nice his purring feels.

Oh, god. He likes Keith back.

He has to tell him.

When he sees Keith at a meeting the next morning, distinctly with a lot more purple fur and pointier ears than before, he sidles up to him with a warm smile.

“Hey, Keith,” he says, trying to keep himself calm as to not give anything away to that Galra nose of his. “We should do lunch.”

Keith looks at him funny. Fuck. ‘Do lunch’??? What is wrong with him?

“Okay.”

“Cool.” It is then that a recess is called, saving Shiro from himself. he books it out of the meeting room before he can make any more of an idiot of himself.

He uses the break in the meeting to go to the kitchens and fetch the carefully craft sandwiches he made the night before. He didn’t fry anything, avoided cutting things if he could, and then stuffed as much roast beef in as he could. Keith devours red meat. It’s so cute. Shit… Shit, Keith is so CUTE.

He tries to swallows his nerves, puts some tea in a thermos, then shoves the picnic in his bag for later. Then he goes back to the exact same meeting room, standing up at the front this time, talking the crew through further relief efforts.

And then Keith fucking lunges across the table and wraps his hands around an alien ally’s throat.

“Holy shit!” Lance screams.

“Oh my god! Oh my god!” Hunk yells. “What do we do? What’s happening? Does Keith have space madness? Space rabies?”

Pidge just covers her face with her hands. Valid.

“Keith,” Shiro says, scrambling to his side desperately. “Keith, let go. Keith!”

Oh, god. Keith’s got a tight grip. His nails-no, CLAWS-are digging into the alien’s glistening, pearlescent skin, worryingly close to something that looks pretty vital. Shiro can’t risk pulling him off like the other time.

“Keith,” he tries, desperate. “Keith, please. Keith, there’s nothing- you don’t need to protect me!”

Keith is not listening. Purple fur is breaking out over every remaining peachy inch of him. His eyes are golden and dangerous. His claws are getting longer.

“You don’t need to protect your claim on me!”

Keith’s ears perk, which is apparently a thing they do now.

“I’m yours,” Shiro tries. He reaches out, carefully, and puts a hand on the back of Keith’s neck. “Keith. Keith, I’m YOURS.”

A sound akin to a chirp comes from Keith’s throat.

“Yours,” Shiro says again, and then, with at LEAST 20 people, including 5 Galra watching, Shiro leans in and nuzzles at Keith’s neck, burying his nose into a slick spot where a good, musky smell is emanating.

"Keith, baby, mate, please..."

Keith's hold loosens, and then is completely gone as he occupies himself with wrapping all around Shiro, clinging to him and purring.

Kolivan clears his throat. "I believe this meeting should be postponed until another time," he says, fixing Shiro with a meaningful look.

There is a vague murmuring of agreements, and the meeting is officially postponed.

Shiro carries Keith back to his quarters with as much dignity as he can, which isn’t much considering the way he’s clinging to Shiro like a very happy koala. He tries to set him on his bed, but he isn’t letting go.

Actually, he’s doing more than not letting go. He is nuzzling at Shiro’s neck very insistently, snuffling and inspecting him like he’s expecting something to be there. He is growing more and more irritated when he can’t find it.

“Shh,” Shiro attempts, trying to soothe him when he starts to huff and growl. He pets the back of Keith’s head, behind his ears as he sits them both down on the bed. “It’s okay.” Keith shifts in his lap very adorably, refusing to pull away from his throat.

He’s squirming with irritation, just a bit, and Shiro tries very hard to concentrate on his near-feral best friend’s strange needs, but it is VERY distracting. He barely catches a gasp, and then suddenly Keith is stock still.

He pulls back, looking Shiro in the eyes. He shifts again, grinding with purpose this time and Shiro grunts, definitely blushing, especially when Keith’s expression goes shrewd and pleased. He scents the air and then starts up a slow, torturous grind.

He keeps grinding until Shiro’s dick is straining in his underwear, and then he lifts up his hips, staring at Shiro expectantly. Shiro shoves down his pants. Keith keeps looking at him, so he yanks off his underwear, too, hard dick slapping up against his stomach before being trapped between Keith’s thighs.

“Stars,” Shiro gasps, then tosses his head back before Keith is wrapping a hand around, conscious of his claws, and stroking him with deft skill that makes Shiro oscillate between jealousy and arousal for the few moments he has enough brain power to feel anything but the latter.

Keith’s eyes stay locked on his, watching his expression, listening attentively to his sounds, as he touches him, and Shiro realizes that he’s about to have the most embarrassingly quick orgasm he’s had in a decade.

“Kei-” he groans, thighs trembling. “Oh, fuck. I can’t-”

There’s a flash of those sharp teeth as Shiro comes, and then he clamps his eyes shut, pleasure overwhelming his senses. When he comes back to himself, Keith is licking his hand clean and purring like a very happy cat.

“Keith,” Shiro groans.

“Shiro,” Keith chirps back, then leans down to seal their lips together.

**Author's Note:**

> come play on [twitter](https://twitter.com/hellostarshine_).


End file.
